Low permeation hoses are often used in systems to eliminate or reduce escape and/or infiltration of vapors and/or gases. For example, such hoses may be used in refrigeration systems to prevent leakage of refrigerant vapors from the system into the environment. Such hoses are also common in fuel systems for preventing fuel vapors from escaping to the environment.
Another application of such hoses is in connection with heating systems for supplying and returning water (or other fluid) from one or more heat exchangers. In such applications, low permeation hoses are used to prevent oxygen from entering the heating system, which can result in corrosion of various components such as pumps and valves.
Low permeation hoses typically include an inner tube for carrying a fluid, and a vapor barrier layer surrounding the inner tube. Various other layers typically may surround the vapor barrier layer, such as a braiding, an outer tube, a cover or outer sheath, etc.
One type of hose that includes a metal foil as the vapor barrier layer is disclosed in U.S. Pat. No. 6,074,717. This patent describes a flexible hose including an inner tube, an aluminum vapor barrier layer formed from aluminum foil that is wrapped in overlapping fashion around the inner tube, and an outer tube surrounding the aluminum barrier layer. The aluminum barrier layer is bonded to both the inner tube and the outer tube. While this design may provide a hose that resists delamination of the tubes and/or the aluminum layer, the wrapped aluminum forming the barrier layer does not provide a continuous sealed barrier layer.